Sand-blast process



im Modem E. EJIAEWS.

SANS BLAST PRQGESS.

No. l I Paent Juy ff, i835.

lierre rares herinner risica,

JEREMIAII E. MATIIEVSON, OF SHEFFIELD, ENGLAND, ASSIGNOR 'IO BEN- JAMIN G. 'IILGHMAN, OF PHILADELPHIA, PENNSYLVANIA.

SAND-BLAST PROCiSS.

SPECXFCATIQN `forming part of Letters Patent No. 321,512, dated July 7, 1&85.

Application filed November 19, 1854. (No model.)

.To @ZZ whom it may concern:

Be it known that I, J nnnMIai-r EUGENE BIATHEWSON, residing in Sheffield, England, have invented certain Improvements in Sand- Illast Process; and I do hereby declare that the following is a full and exact description thereof.

My invention relates to the production of a stream ot' sand moving at a high velocity to be used for cutting and grinding hard substances in the manner now generally known as the sand-blast process. l Heretofore in Working the sand-blast process the velocity has been given to the sand either by a jet of steam or a current of air. A jet o' steam is the more simple, powerful, and economical agent; but it has the inconvenience of heating the article operated on, (which, in the ease of glass, may tend to break it,) and also of wetting it,whieh would damage patterns made ot' paper, glue, and similar substances, and would cause the wet sand to clog the iine lines of the design. A current of air avoids these difficulties, but is more expensive in apparatus and power, and also makes a great dust, which requires close chambers to Work in, and is very destructive to apparatus.

My invention consists in combining together a jet ot' steam and a current of air in such a manner that the jet of steam gives the velocity to the sand, While the current of air, moving in a different direction, carries away the steam before it reaches the article operated on,\vhich thus remains comparatively cool and dry. This combination may be conveniently effected by causing the jet of steam to propel a stream of sand through a close cylinder, entering at one end through a hole closely fitting the sand-blast pipe and passing out of the other end through a hole just large enough for the passage of the cone of flying sand. Gonnected with the cylinder is a ventilation-pipe, through which a current of air is thrown outward, (preferably by a steam-jet.) This air is forced to enter the cylinder through the same hole by which the sand is ilying out, and it thus meets and drives back the steam and damp air which are mixed with the sand, and carries them away through the ventilationpipe, While the sand, becoming thus dried and cooled, ies on its course unt-il it strikes the object to be operated on.

The following is a description of a method of carrying my invention into effect, taking,for example, the grinding by the sand-blast of an article small enough to be held in the hands.

Referring to the drawing, A is a cylinder of sheet-iron about eighteen inches in diameter and two feet high. B is a sand-blast pipe pointing upward through the center of the lower head of A. C is the upper head of the cylinder, made of iron about one-quarter of an inch thick, and having in its center a hole, D, about four inches in diameter. E is a ventilation-pipe, about four inches in diameter, leading either into the open air or into a settlingchamber, and provided with a steam-jet, F, to create a draft.

The way of working is as follows: Steam is turned on to the sand-blast pipe B,and a stream of sand and steam is proj eeted through the hole D. The steam is then turned on to the jet F, so as to cause a current of air to enter the hole D, which drives back the steam and moist air, but allows the sand to pass on. The article to be operated on, G, is then held and moved about in the path of the sand, about three or four inches above the plate C, the hands being protected by gloves. The valve-cock of the steam-jet F should be regulated so as to make the current of air entering the hole D just strong enough to prevent the escape ot' any visible vapor and to keep the Work cool and dry. Any greater rapidity is useless,and even hurtful, as tending to lessen the velocity oi' the sand.

To prevent the scattering of the sand and dust into the room the upper end of the cylinder A may be inclosed in a Working box provided vrith a Window and holes for the arms ot' the Workman, so that he can manipulate the article from the outside.

lThe steam-jet, sand-tube, and nozzle-tube, constituting the sand-blast pipe or sand-propelling part of the apparatus, may be made and operated in the same Way as those in common use for the sandblast process -which are noiv Well known and have been described in published works, and particularly in the patent granted to B. C. Tlghman, No. 108,408, and I do not mean to claim or to confine myself to any particular apparatus or' method for causing a jet of steam to give velocity to the sand. I am aware that in said patent it is stated that the sand may be impelled by a mixed current of steam and air produced by a steamjet in the ordinary manner, but in that case the air moves in the same direction as the steam and helps to give velocity to the sand, and all the heat and moisture produced are thrown upon the article operated on, whereas in my invention theair moves in a different or contrary direction to the steam, and in some degree lessens the velocity of the sand, While its essential function is to remove the heat and moisture before they reach the article operated on.

I have described an apparatus in Which my invention can be conveniently carried out; but I do not mean to confine myself thereto. The

form oapparatus may be varied to suit the nature and shape of the article operated on, and any form of apparatus may be used in Which a current of air is made to remove the heat and moisture from a stream of sand to which velocity has been given by a jet of steam.

I do not claim anything that is described in the patent granted to B. C. Tilghman, dated October 18, 1870, No. 108,408.

What I claim as my invention is In the sand-blast process, the method 'of drying a jet of steam-driven sand, Which consists of causing a reverse or cross current of dry air to pass through the sand-j et, substantially as shown and described.

J. E. MATHEWSON.

Witnesses:

EDWIN HOLE,

A 17 Oaqford Street, Szeeld. F. F. HIBBERT,

Clerk, U. S. Consulate. 

